The Vanguard-class submarine HMS Vigilant, one of four Royal Navy submarines armed with Trident missiles, is seen in January at HM Naval Base Clyde, also known as Faslane, Scotland. British lawmakers voted Monday to renew the country's fleet of nuclear-armed submarines, a powerful but expensive symbol of the country's military status.

The British government voted Monday to renew its nuclear deterrent, replacing its aging fleet of nuclear-armed Vanguard submarines with four new ones, to be named Successor.

But the vote was by no means unanimous, with 117 members of Parliament voting against renewal, compared with 472 who voted in favor.

Digging into the detail of those numbers, however, reveals even more – about the difference in opinion between Scotland and the rest of Britain, as well as the divisions within political parties and the political considerations tied to this vote.

“Britain’s nuclear weapons have long been about role and prestige, something that applies to all nuclear powers to varying degrees,” says Tim Oliver, Dahrendorf Fellow on Europe-North America Relations at the London School of Economics and Political Science. “Britain giving up its nuclear status now would have been as big a message as Brexit in signaling to the world that the UK was less interested in being a global power.”

But this in itself prompts one of the fundamental arguments of the nuclear program’s opponents: that political concerns and motivations play too big a role, that the fundamental reason for having a nuclear weapons capability – deterrence – no longer stands up under scrutiny.

One specific point made in this regard is that new technologies, such as naval drones and cyber capabilities, will soon render the submarines vulnerable to detection and destruction before they can retaliate, thus defeating the purpose of the Trident nuclear missiles they carry and the entire nuclear program itself.

Yet, as countered by David Blagden, a professor in the Strategy and Security Institute at the University of Exeter, England, “such emerging technologies face potentially insurmountable technical mountains of their own” before they can represent a credible threat.

But there are other reasons for protest, too: principled opposition to weapons of mass destruction, concerns over the cost, a belief that Britain could lead the world in disarmament, and a desire to see the money spent in other areas of defense, such as conventional forces, or other areas of the domestic economy in general.

Yet Britain’s new prime minister, Theresa May, was unequivocal in her first parliamentary statement since taking office.

“It is impossible to say for certain that no extreme threats will emerge in the next 30 or 40 years to threaten our security and way of life,” said Prime Minister May. “And it would be a gross irresponsibility to lose the ability to meet such threats by discarding the ultimate insurance against those risks in the future.”

Certainly, international considerations played a role in May’s stance, not least in demonstrating support for NATO: Britain is one of only three members possessing nuclear weapons, the others being the United States and France.

But domestic politics were also front and center. The new prime minister, who came to power after David Cameron resigned and thus has no electoral mandate of her own, was also seeking to solidify support within her own party, as Andrew Dorman, a professor of international security at King’s College, London, explains.

“In addition, it was a way of highlighting divisions in Labour [the main opposition party],” says Dr. Dorman, who is also editor of the Chatham House journal, International Affairs. “The front bench mostly wants to scrap Trident, but many backbenchers are in favor of keeping it.”

Labour’s current leader, Jeremy Corbyn, who is facing a leadership challenge in the wake of Brexit, is taking a very different stance on Trident compared to his predecessors. His opposition to the program contrasts starkly with that of Tony Blair’s Labour government, which was in fact responsible for setting the wheels in motion for today’s renewal by the publication of its white paper entitled “The Future of the United Kingdom’s Nuclear Deterrent.”

In Monday’s vote, 140 out of 230 Labour MPs backed the prime minister’s proposals for Trident’s renewal, contrary to their leadership’s position.

Yet a starker statistic still is apparent when considering the 57 Scottish MPs. Only one of them, the single Conservative representative, voted with the government. The one Labour MP, one Liberal Democrat, and 54 Scottish National Party MPs all voted against.

“The Scotland factor is a complete and utter minefield, if you’ll excuse the pun,” says Dorman. “Westminster [where the British parliament is located] doesn’t want to deal with this issue, but might have to.”

Scotland is indeed a tricky topic for Britain, right now. Having already had a vote on independence in 2014, in which the Scots opted to remain in the United Kingdom by 55 percent to 45 percent, they then voted by more than 60 percent to also stay in the European Union, when Britain held its recent referendum. But the rest of the UK outvoted them, and Brexit won.

This has put the question of another independence referendum firmly back on the table. Add to that the fact that Britain’s nuclear submarines are headquartered at a Royal Navy facility in a Scottish loch, and the “Scotland factor” that Dorman refers to is explained.

Yet if the British government were to relocate that headquarters (quite where would offer a viable alternative is another difficult question), one fear is that it could catalyze the secession of Scotland, as the nationalists might portray it as something of a betrayal.

But if Scotland votes for independence, and the nuclear submarines are still stationed north of the border, what then? Would the newly independent government evict the fleet? Would they charge exorbitant rent?

These are the questions facing policymakers in Westminster. But one thing seems certain, at least for now: Britain will be keeping its nuclear deterrent.